Fibrous glass felt



FIBROUS GLASS FELT Filed Dec. 24, 1936 5 Sheets-Sheet 1 ZNVENTOR BY A TTORNE Y5 July 2, v SLAYTER FIBROUS GLASS FELT I Filed D90. 24, 1936 5 Shee'ts-Sheet 3 INVENTOR BY 4%M W W ATTORNEY;

July 2, 1940. a SLAYTER 2,206,059

FIBROUS GLASS FELT Filed Dec. 24, 1936 5 Sheets-Sheet 4 W479 11v VENTOR A TTOR/VE y:

llllu July 2,1940. G, SLAYER 2,206,059-

FIBROUS GLASS FELT Filed Dec. 24, 1936 5 Sheets-Sheet 5 Patented July 2, 1940 UNITED sTArEs FIBROUS cuss ram Games Slayter, Newark, Ohio; assignor, by mesne assignments, to Owens-Corning Flberglas Corporation, a corporation of Delaware Application December 24, 1936, Serial No. 117,589

11 Claims." (01. 154-44) The present invention relates to a novel method and apparatus for forming an interfelted mass of glass wool in which the individual fibers, which because of their original long and fine nature inherently tend to lie parallel to a particular plane or surface upon which the fibers are accumulated, are caused, nevertheless, to partially depart from this inherent parallelism and interfelt throughout the mass of glass .wool, to the end that the mass may attain mass integrity and tensile strength in all directions including directions transverse to the original plane or surface of inherent parallelism.

An object of the invention is to produce an interfelted product of glass wool having not only mass integrity and tensile strength in all directions but which is high in heat resisting and heat insulating quality. In order to procure a high insulating value from a product having long fibers, it has been found advantageous to lay the fibers predominantly transverse ,,to the direction of heat flow. When the fibers are laid transverse to the direction of heat flow, the heat is prevented from flowing through the mass with 35 the same ease as when the fibers are laid parallel to the direction of heat flow. It is an object, therefore, to provide a product in which the longer fibers predominantly do not lie in the direction of heat flow but have their major com- 'ponents extending in directions transverse to the direction of heat flow.

" Another object of the invention is to provide a mineral wool mass having the foregoing characteristics which is flexible and resilient, so that 35 when walked on or otherwise compressed or flexed, it will yield but will spring back substantially to its former shape and position when released. The so-called masses of mineral or rock wool heretofore and at present in general use, have serious objections as they lack the desirable features above noted which characterize the present invention. Such masses are generally a molded productand in view of the shortness of the fibers derive substantially all of their strength 45 from the binding material. As a result, these products are solid, rigid and inflexible. When such material is stressed or bent, solid portions of it crack off and break away, and when the material is walked on or compressed, the mass 50 merely crumbles and cannot resume its former shape or position. Moreover, in forming pipe covering of this material, the product has to be formed into two separate solid blocks which are generally hinged together along their longitudi- 55 nal edges. If one of these halves is bent open,

the material refuses to flex but merely breaks off in large pieces. An aim of the, Present invention is to overcome 'the above noted objections and difficulties and produce a felted mass which may be flexed and bent to a reasonably 5 high degree and which does not crack off into large pieces.

Another object of the present invention is to provide an interfelted, bonded mass of glass wool of light density, the density being of the order 10 of magnitude of about 3 to 12, andv preferably about 5 to 7 pounds per cubic foot, and having great strength although replete throughout with a multiplicity of dead air spaces.

Another object of the invention is to provide a felted mass with the foregoing characteristics, having a predetermined shape and size, depending on the particular use to which it is to be put, as, for example, pipe covering, stove or refrigerator insulation, wall boards or the like. to

Another object of the invention is to provide it felted mass of the foregoing characteristics in which a large portion of the glass fibers may remain long and reticulated and mutually interlaced and extending in all directions.

A further object of the invention is to produce mats of the foregoing characteristics having various binders suitable for various specific uses and in particular for use as a high temperature heat insulation product.

A further object of the invention is to provide methods of and apparatuses for interfelting'a conventional glass wool mat having long fibers in substantial parallelism, the said methods producing an interfelting without causing the mat to tear apart or become weak or infirm, and without causing the individual'fibers to break up into a mass of short fibers such as conventional rock wool or the like.

Other objects and advantages of the present 40 invention will become apparent from the following description taken in conjunction with the accompanying drawings, in which:

Fig. l is a fragmentary elevational and diagrammatic view shown partly in section of an apparatus for forming a conventional glass wool mat and thereafter causing it to be interfelted and bonded;

Fig. 21s a planview of the interfelting apparatus shown in Fig.

Fig. 3 is an end view shown partly in section of the same apparatus, the section being taken at the line 3-3 of Fig. 1;

Fig. 3A is a diagrammatic side view of amodified embodiment of a portion of the apparatus a adapted to juxtapose a plurality of layers oi. glass wool mats or webs;

Fig. 4 is a diagrammatic elevational view shown partly in section of an apparatus for forming a glass wool felt and a modification of the interfelting means;

Fig. 5 is a plan view of the modified embodiment of the felting apparatus shown in Fig. 4;

Fig. 6 is an end view of the same modification illustrated in Figs. 4 and 5, the section being taken on the line 6-6 of Fig. 4;

Fig. '7 is an elevational diagrammatic view of an apparatus for forming a glass wool mat and means for intermixing a suitable binder therewith and then rolling said mat upon a mandrel or the like, preparatory to the interfelting action;

Fig. 8 is a diagrammatic elevational view shown partly in section of a means for interfelting a pipe cover or insulation roll and an oven for drying and causing the interfelted mass to solidify in permanent formation;

Fig. 9 is a longitudinal cross-section of a pipe covering of glass upon a mandrel showing details for permitting it to be reduced to a predetermined size;

Fig. 10 is a diagrammatic elevational view of a modification of the interfelting means when applied to a. cylindrical shaped insulation such as a pipe cover;

Fig. 11 is a sectional diagrammatic and elevational view of a further modification of an interfelting means designed to interfelt a cylindrical shaped mass;

Fig. 12 is a sectional end view of the embodiment shown in Fig. 11, the section being taken along lines l2--l2 of Fig. 11;

Fig. 13 is a diagrammatic sectional view of a still further modification of an interfelting means for cylindrical masses;

Fig. 14 is a sectional perspective view of a pipe cover shown in place over a pipe; and

Fig. 15 is a diagrammatic sectional view of a modified embodiment of a drier for the glass wool mat.

With reference to conventional methods of making insulating material of the general type hereinbefore mentioned, when short hairy fibers are used such as those produced in the common rock wool or mineral wool operations, the fibers are commonly so short that it is impossible for them to 'interlace and mesh with one another to produce substantial mass integrity and inherent strength. For this reason various bonding agents are commonly intermixed with such materials, these bonding agents being products such as asphalt or the like, which more .or less completely fill the interstices between the fibers and in any event cause a rigid high density product to be produced such as a cement product or board.

0n the other hand, when mats comprising long fibers are produt ed, such as those mats formed by the deposition of long, fine, glass fibers, the inherent arrangement of these fibers is more or less completely parallel to the surface upon which the fibers are accumulated or disposed. There is little, if any, departure from the original parallelism. The fabric can readily be cleft or separated along surfaces parallel to the fibers without material resistance from the mat itself. In other words, the mat inherently lacks mass ,integrity and tensile strength in directions transverse to the mat. I have found, however, that by means of the present method as described more fully hereinafter, it is possible to produce a mat which utilizes the inherent orientation of the fibers and yet which possesses mass' integrity and strength in all directions throughout the mass.

One of the features of the present invention is the production of insulating material comprising a mass of long mineral wool or glass fibers which lie predominantly in a plane or surface transverse to the direction of heat fiow through the material but in which a large portion of the fibers have departed from parallelism with said plane and have been caused to interweave and interlace with the fibers which remain parallel with said plane. There is thus produced a felted mass having strength and mass integrity in all directions including the said transverse direction. Another feature of the present invention is the production of a heat insulating material which, while being interfelted, is, nevertheless, laminated to such a degree that it possesses a high degree of flexibility, yieldability and strength in all directions and also possesses a high degree of insulating value.

Another feature of the present invention relates to a process of felting a mat in which there is produced a series of successive short relative movements between the upper and lower surface portions of the mat, the movements being more or less in the direction of the surface of inherent parallelism. When layers of fibers parallel to a particular plane are juxtaposed and then caused to slide upon one another in a particular direction for a short distance, the fibers of each of these layers tend to interfelt and depart to a certain extent from the initial parallelism. If these layers are again given another short relative movement, they are permitted to further interfelt and further depart from their initial parallelism to the surface. If the individual movements, however, are excessive, the mat is merely torn apart without accomplishing the desired purpose. Mere agitation without intelligent guidance, therefore, is not sufilcient. As these movements or impulses are repeated for a sufllcient number of times, it is possible to cause a thorough interfelting, which I have so termed,

having in mind a mass of fibers interlaced and extending in all directions including directions transverse to the original inherent parallel surface, although having components of direction predominantly parallel to the original parallel surface.

I have found that while repeated movements or impulses cause an interfelting action, it is generally preferable to produce these movements or impulses in the same direction or in more or less the same effective direction as brought out more fully hereinafter. When laminations or layers of fibers arranged in parallel planes are juxtaposed to one another and caused to slide upon one another in a particular direction for a short distance, the fibers of each of these laminations tend to interweave, interfelt and depart from the initial parallelism. If these laminations are then moved back again to their original positions, the individual fibers tend in part to resume their initial positions and regain substantial parallelism to the principal surface.

However, if successive impulses are given to the juxtaposed laminations in the same direction or at least in the same effective direction, as brought out more fully hereinafter, the fibers do not resume their original positions but continue to interfelt and intertwine and depart to a predetermined degree from the original parallelism. The result is that the original laminations are caused to be interfelted and a certain portion of the juxtaposed fibers are caused to intertwine and, in-

crease the mass integrity of the mat in the direc tion transverse to the original surface of parallelism; However, the fibers, and particularly the longer fibers, remain predominantly in directions approaching more or less closely, their original parallelism so that the original laminations.

are not necessarily entirely removed and the benefits derived from arranging the major portion of the fibers and particularly the longer ones transverse to the heat flow, are retained. Many of the shorter fibers thus extend in directions transverse to the major faces of the mat and thus serve to add strength in these directions, leaving longer fibers principally lying in planes parallel to the major faces and serving to retainthe strength of the mat in these directions.

The successive impulses or short relative movements in the same direction between two adjacent laminations may be produced by several methods, according to the product which may be desired, as brought out more fully hereinafter.

Another important feature of the present invention is the discovery that the use of alarge amount of water or other suitable liquid throughout the mass of fibers materially assists in the interfelting action. For this purpose I preferably drench the fibers with a large amount of binder solution prior to the interfelting action. The liquid performs two principal functions, (1) it lubricates the fibers and permits them to slide past one another during the interfelting action, and (2) the forcible removal of the liquid from the fibrous mass, as, for example, by centrifugal force, causes, displacement of the fibers from their original orientation. Thus, the mere fact that the fibrous mass has been drenched with a suitable liquid facilitates the interfelting and consequently increases coherence of the mass as a whole.

The liquid, which 'may be caused to fill the I interstices between the fibers originally, may

weigh as high as ten or more times as much as the fibers, owing to its heavy concentration throughout the mass. As the liquid is removed from the mass of fibers either bycentrifuging, suction, or other suitable means, it causes the fibers and particularly the shorter fibers, to be displaced from their original position and approach an alignment in the direction of removal of the water. the direction transverse to the original inherent parallelism, the fibers tend to align themselves in the transverse direction and thus facilitate an interfelting of the mass.

In carrying out my invention it is possible to produce articles of cylindrical or curved form for various uses such as pipe covering or the like, or in planular form for various uses as, for example, insulating stoves, refrigerators, wallboards or the like, or any other shape desired.

Referring now to the drawings, Fig. 1 shows an apparatus for producing glass wool bats and a method of formingthem into an interfelted mass. A glass melting and refining tank or forehearth 20 is shown in which a head of glass is maintained. The molten glass flows continuously through feeders 22 in the floor of the furnace in a multiplicity of small streams which are acted upon by blowers 23. The issuing streams of glass are enveloped by the downward blast of steam or other gas supplied bythe blowers and are thereby continuously drawn out to fine fibers or filaments 24.

When the liquid is'removed in' spouts 26 are preferably of streamline forma-' tion, the walls of each spout being downwardly divergent and having their upper marginal portions 21 curved to provide a flared mouth. The spouts 26 are preferably of the venturic type, the shape and arrangement being such that a draft of air is induced from the drawing force of 'the steam blast and a considerable volume of air is drawninto and intermixed with the steam.

The lower ends of the spouts 26 open into an expansion hood or chamber 28 which is also preferably of streamline construction and forms an accumulating chamber within which the fibers from the spouts 26 are laid upon and intermatted on the reticulated conveyor belt 30 to form a mat 3|. The conveyor belt is supported on rollers 32 and continually advances, carrying the mat 3| forward as it is formed. At the front end of the hood or chamber 28 is a skirt 33 which overlies the mat and tends to compact it to a predetermined depth as the mat emerges from the hood 28.

Arranged below the belt 30 and in register with the hood or chamber 28 is an exhaust chamber 35 having an exhaust outlet 36. If it is desired, suction may be applied to the outlet 36. Mounted preferably in the hood are one or more adjustable spray gun nozzles 40 which are aimed upon the mat as it is being formed and serve to apply a suitable coating material to the mat. Various coating materials have been found advantageous for glass wool, such coating materials being oils, soaps, gelatins and other suitable plastics or oleaginous substances, and it has also been found advantageous to incorporate a suitable free acid radical'to counteract the presence of alkali in the glass which may leach to the surface.

During the formation of the mat upon the belt 30, the fibers descend upon the mat in such a manner that they inherently all lie parallel or substantially parallel to the belt itself. That is to say, as the long, fine, attenuated fibers are arrested upon the mat, they weave back and forth over the belt and build up in layers, all of which'are parallel to the belt 30. A mat of this characteristic has little tensile strength in a direction transverse to the belt itself for it is generally a simple matter to lift the layers of fibers apart layer by layer.

In carrying out my invention, I have provided various apparatuses for interfelting the glass wool mats to a predetermined degree. One of these apparatuses adapted to interfelt the individual layers of glass wool into a planular form, has been illustrated in Figs. 1 to 3. Referring to Figs. 1 and 3, the mat 3| as it is formed, is advanced continuously by the belt 30 and passes under spray nozzles 43 adapted to apply a large amount of dilute binder solution throughout the mat. The excess solution flows down through the mat and into a trough 44 underlying the belt 30.

After the material is soaked with 'the binder solution, the advancing mat 3| passes between two coacting caterpillar belts 45 and '46, the inner surfaces of the belts 45 and 46 being juxtaposed upon the mat 3| and moving concurrently with and at substantially the same speed as the mat;

The belt 45 runs over drurnsll which are mounted upon a stationary frame 48 and the belt 46 runs over drums 58 which are mounted on a rectangular frame The frame 5| is provided at its four corners with posts 52 to each of which is imparted a circular motion in a horizontal direction. In order to produce this circular motion the posts 52 are mounted on eccentrics 58 which are fastened to vertical shafts 54a and 54b. Two of these shafts 54a are preferably power driven by means of gears 55 through gears 56, shafts 51, intermeshing conical gears 58, shaft 59, gear box 68 and motor 6|. The remaining shafts 54b may be idlers or merely form bearing supports for the superposed posts 52.

The belt 45 may be driven by any suitable means as, for example, by being interconnected to the belt 30 by means of a chain 53 or other suitable means. The belt 46 is provided with a driving means comprising a motor 65 gear box 86, drive belt 61 and gear train 68, all of which are preferably mounted upon the frame 5|.

The operation of this device is such that the mat, in passing between the juxtaposed belts 45 and 46, is interfelted and partially compressed. As the mat 3i passes between the belts 45 and 46, the upper belt 46 is given a horizontal circular movement preferably of about inch diameter or so, in a plane parallel to the surface of the mat. The space between the belts is gradually tapered from the charging end to the discharge end of the line so that, for example, if a 4 inch glass wool bat soaked with binder were fed in at one end, it may be felted into a mat of, say, about 1 inch in thickness according, of course, to the degree of interfelting and the density desired.

The relative circular movement between the two belts causes an interfelting between the parallel layers or fibers whereby a certain portion of the fibers lying parallel to the surface of the mat are caused to depart from the original parallelism and are caused to intertwine and interlace with the adjacent layers to produce an interfelted mass.

The circular motion made possible by the mat, it will be noted, causes any two juxtaposed points upon respective layers of fibers to receive impulses or relative movements in only one direction, that is to say, as one point is moved in a circular motion relative to a second juxtaposed point, the second point passes the first point in only one direction. When passing back in the other direction, it will be noted that the second point is at a distance from the first point, this distance being comparable to the diameter of the circular motion. It has been found that mats of glass wool given this type of motion are caused to interfelt and produce a fibrous mass having an interfelted appearance in which the individual fibers in parallel layers are caused to interfelt and intermat to a predetermined degree.

The binder which is added to the mat is preferably a dilute solution, say, 1 to of a suitable binder such as starch, bentonite, casein, dextrin, agar agar, gelatin, rubber, asphalt, etc. The solution of binder performs two principal functions, (1) it serves as a lubricating medium between the fibers during the interfelting action, and (2) after the interfelting action the solution may be dried, leaving the binder coating the fibers and binding interadjacent fibers preferably at points of intersection, whereby a flexible porous mass is produced. The binder solution, being dilute, permits the binder to be distributed uniformly throughout the mass and when the solution has been evaporated a relatively small amount of binder remans. I have found that small amount, such as 1 to 10% binder, and preferably about 2 to 5% binder, is sumcient for most purposes.

Referring more particularly to Figs. 4 to 6, another embodiment of the present invention is disclosed in which a planular interfelted board or cake of glass wool may be produced. In this embodiment the method and apparatus for forming a mat of glass wool may be of any particular type, one of which has been diagrammatically illustrated in Fig. 4 and is similar to that described in Fig. 1. Here, again, it will be noted that the mat 3| is soaked with a suitable binder, the overplus of which drains into the trough 44. From here the mat advances from the conveyor 38 to another conveyor belt 88 which may run over rolls 8|. Mounted over the conveyor belt 80 and coacting therewith are a series of rollers 83 which are interconnected by chains or interconnecting links 84 in endless formation. Each of the rolls 83 is also provided at its outer extremities beyond the links with outwardly extending lugs 85 which engage with the gear teeth 86 of sprocket wheels ll. The sprockets 81 are keyed to shaft 88 and 88a which revolve in bearings 89 of the framework 98. The shaft 88a near the discharge end of the device is preferably provided with suitable driving means such as a motor 8|. Driving connection between the motor 9| and the shaft 88a may be made through a pulley 92, drive belt 93 and gear box 94, the latter being actuated directly by the motor 9|. The pulley 8| is also provided with a driving means such as the motor 95, gearing within the gear box 96, the interconnecting drive belt 91 and the pulley 98. If preferred, both the belt 89 and the rollers 83 may be driven by other suitable means or by theisame motor or power unit.

The motor 9| advances the rollers 88 over the mat 3| in the same direction as the mat is moving although at a speed preferably greater than that at which the belt 88 is traveling. This causes each roller 83 to impart to the material forming the mat, a progressive wave-like or rolling movement, each wave advancing relative to the mat.

By regulating the speed of the rollers relative to the speed of the mat 3|, it is possible to regulate the number of times the mat receives a rolling action. It will be noted that with this arrangement, it is possible to provide a machine which takes up little room and yet applies to the mat any reasonable predetermined number of impulses, wave-like motions or rolling actions. as desired.

The rolling movements upon the mat 8| cause the upper surface of the mat to advance a short distance forward relative to the lower surface of the mat. One factor assisting in the interfelting of the glass fibers is a small node or swelling which forms in front of and precedes the roller 83 in its passage across the mat, this node causing the fibers to be raised a certain extent and permitting adjacent lines of fibers to interlace and interfelt more completely. In this connection it is to be noted that the present apparatus serves to provide successive relative movements in the same direction between adjacent layers of fibers, all of which lie originally substantially parallel to the principal surface of the mat. As these successive movements in the same direction are given to the mat, a large portion of the fibers, starting particularly at the ends thereof or loops therein, are caused to interlace and interfelt and provide a mass integrity and strength to the mat in the direction transverse to the principal surface thereof. After the mat has been interfelted, it is conveyed through a drying oven I00 which serves to remove the water present in the solution and thus permits the binder present in the original solution to solidify and cause the adjacent fibers to be held firmly together.

Referring more particularly to Fig. 3A, I have illustrated an apparatus adapted to juxtapose a plurality of mats of glass wool fibers preparatory to forming them into a felted planular mat or board by a process and apparatus such as those illustrated in Figs. 1 to 6. In this apparatus a plurality of mats or webs 265, which have been formed on a suitable forming machine such as illustrated in Fig. 1 or 4, are fed in over supporting means or chutes 266. The supporting members 266 prevent the mats or webs 265 from pulling apart or otherwise disintegratmg.

The mats or webs 265 as they advance beyond the supports 266 are brought into juxtaposition with one another between the coacting belts 261 and 268 which lie on each side of the juxtaposed mats. Spray guns 210 are mounted over the juxtaposed mats or webs 265 and cause a large amount of preferably dilute binder solution to drench and thoroughly soak the mass of glass wool fibers. A trough 21I underlies the belt 261 to collect and conserve the excess liquid which may run through the mat. The juxtaposed layers 212, after having been drenched with a suitable liquid, may then be fed into one of the interfelting apparatuses illustrated in Figs. 1 to 6.

When interfelting a. plurality of juxtaposed layers, the fibers of the individual layers are caused to interfelt with the fibers of adjacent layers to produce a coherent mass of glass wool fibers, in a similar manner to that illustrated and described hereinabove or as more fully brought out hereinafter in connection with the other embodiments.

Referring now to Figs. '1 to 9, I have illustrated an apparatus adapted to form an interfelted mass of glass fibers in a cylindrical form suitable for pipe covering or the like. In the drawings, reference character I05 designates generally an apparatus for forming a mat I06 of glass wool or similar material. The apparatus I05 may be similar to that illustrated in Fig. 1. In manufacturing pipe covering, I have found it preferable to form a mat of glass wool, which is relatively thin, and build layers of these mats spirally upon a mandrel. In so doing I have achieved a product which possesses great elasticity, flexibility, strength and also lightness in density. The density is preferably of the order of about 3 to 6 pounds per cubic foot, but it may be produced within a much wider range.

In order to convey the mat I06 from the forming machine, I provide a belt I01 running over rolls I01a. Above the mat I06 are spray nozzles I08 which serve to soak the mat with an abundance of dilute binder solution. The excess binder drips from the mat and through the belt I01 if it is foraminous, and passes into a receiving trough I09 arranged below the belt I01. A conduit IIO'leading out from the trough to return the excess binder solution to the spray nozzles I08. At the discharge end of the conveyor belt I01, the mat I06 is rolled upon a mandrel II2 to the desired thickness, after which it is cut off by suitable means such as knife II3. A driven drum II4 may be provided to assist in the rolling operation of the mat on the mandrel lI2.

Fig. 8 illustrates spinning or interfelting means and a drying element. The spinning I means comprises a forarninous belt I20 which is passed over stationary rolls I2I, I22, I23 and I24 and over movable rolls I25'and I26, these latter being mounted together upon a reciprocable horizontal slide I21. The" belt I20 also passes around a roll I30 which serves as an adjustable take-up roll, the amount of take-up being determined by the particular length of the belt. The slide I21 is mounted upon a frame I28 upon which are also mounted the stationary rolls I2I, I22, I23 and I24 over which the belt I20 travels. v

A handle or lever I29- or other actuating means may be provided for the slide I21 to move it into or out of operative position. The operative position noted as B on the drawings for the slide has been shown in solid outline and the inoperative position A of the slide has been shown in dotted outline. The belt I20 is driven at any desired speed which may vary from a few feet to about 3,000 ft. per minute, although I have found it preferable to drive it at a speed of about 300 to 1,000 ft. per minute for about 500 times. The driving means may consist of a motor I3I which is connected with the roll I22 by means of a drive belt I32 and accompanying pulleys.

A table I35 is preferably provided between the roll H4 and the roll I26, this table I35 serving to feed the pipe covers I36 into the apparatus.

The cylindrical pipe cover I 36 is preferably provided at each end thereof with a. collar or spacer I31 (see Fig. 9), the purpose of these collars being more fully brought out hereinafter.

In starting the operation the holder I29" is pulled over to position A, at which'position the rolls I24 and I25 are spaced apart and the belt I20 hangs limply therebetween. The roll I36 is the fed into the loop in the belt between these rolls and then the handle I29 is pulled over to position B to cause the belt I20 to encircle the pipe cover I36.

When the roll I25 has been pulled into operative position B, the belt is started and revolves the pipe cover I36, preferably at high speeds, thereby causing the binder solution within the glass wool mat to be distributed over the fibers, particularlyat their points of intersection, and the excess to be thrown out centrifugally.

The centrifuging performs the further important function of interfelting the juxtaposed layers of the glass wool mat. It will be noted that before the centrifuging operation, the pipe cover I36 was made up ofa series of layers of glass wool fibers, all of which contained fibers lying substantially parallel to the outer cylin drical surface, and so that the pipe cover I36 could readily be unrolled to its original mat formation or the fibers otherwise lifted off layer by layer. However, after the centrifuging operation, the adjacent fibers from juxtaposed laminations of the glass wool mat are caused to depart to a certain extent from the original parallelism and interweave with one another,

whereby the strength and mass integrity of the matted roll is materially increased.

The interfelting action is facilitated to a large extent by the successive revolutions of a node or swelling I40 (Fig. 8) which appears in the pipe cover I36 between the rolls I24 and I25 during the rolling action. A portion of the glass wool is forced up between these rolls to form the node and, in revolving around the pipe cover, the

belt I20 in the correct position. If the roll is placed in the incorrect position, the spirally wound mat tends to unwind and be destroyed.

The spacers or collars I31 (see Fig. 9). at each end of the roll I36 enable the compacting of the glass wool mat to be carried on to a predetermined degree and also facilitate the production of a more or less perfect cylindrical surface. The collars I31 may be made of wood, metal or other suitable material and may be fitted onto the mandrel in any suitable manner.

After the interfelting action, the collars I31 may be removed and the pipe covers I36 are then placed in a drier or oven I45 which will now be described. The oven consists of a chamber I46 having a charging opening I41 at one end and a discharge opening I48 at the other end, each opening being provided with a sliding gate I41a and I48a, respectively, which serves to seal in the heat within the chamber.

Overlying the floor of the chamber I46 are a series of spaced apart parallel rollers I50, all of which are rotated in the same direction so that the upper portions thereof are advancing toward the discharge end. The rollers I50 may be driven by any suitable means such as a motor I5I which may be mechanically connected with the rollers I50 by means of a speed change gear box I52, power belt I53 and suitable gear or belt mechanism (not shown) interconnecting the individual rollers I50. In proximity to the charging opening I41 is a table or chute I55, this chute serving to introduce the individual pipe covers I36 after they have been interfelted and left the spinning mechanism.

A predetermined temperature and humidity may be maintained in the chamber I46 by passing a fiow of -air therethrough, preferably in a counter-current direction with the movement of pipe covers I36. For this purpose a hot air inlet I51 may be provided near the discharge end of the chamber I46 and an air outlet I56 may be provided near the inlet I51.

The rolls I36 are introduced into the chamber through the inlet I51 and seat themselves between adjacent rollers I50. As the pipe rolls rest between the adjacent rollers I50 they are given a rotary motion in a direction shown by the arrows in the drawings. The revolving of the rolls which is generally done at a relatively low speed, serves to maintain an even distribution of binder throughout the pipe covering and prevents a seepage of the binder to any particular point or side.

In loading the pipe covers I36 into the oven, it is possible to pile them up into successive rows, the covers of each row, of course, rotating in the thereon by turning the crank I61.

direction opposite the direction of rotation of the covers in the adjacent rows. In order to advance the pipe covers I56 through the oven, it is merelynecessary to advance the first cover nearest the charging end I41 and cause it to bump against the next succeeding pipe cover. This next cover then advances automatically to the next succeeding space and causes in turn its next succeeding pipe cover to advance one more space. This successive advance of positions occurs very rapidly throughout the oven. In other words, by moving the first cover, all of the covers in order are advanced to the next succeeding'position, and the last covers I36 in the oven are caused to fall out of the discharge end The continual rolling of the pipe covers I36 on the rolls I 50 within the oven also assists in producing a smooth, tough and finished surface on the individual pipe covers. As the solvent of the binder or other liquid therein evaporates and is carried off through the outlet I56, the binder hardens and produces a stiff, flexible and strong product having a tough, coherent surface.

After the solvent or other liquid in the binder solution has dried, a relatively small amount of residual binder remains in the pipe cover to serve as a binding agent. I have found that a small amount remaining, such as 2 or 3%, compared to the weight of the glass fibers, is generally suificient to form a strong, coherent and interfelted mass which also has the advantage of flexibility and yieldability under pressure. The amount of binder left in the cover is dependent upon the original concentration of binder solution, the amount of solution applied and the degree of centrifuging.

Referring to Fig. 10, I have illustrated a modification of the spinning apparatus illustrated in Fig. 8, In this embodiment a mat of glass wool I 60 is illustrated being carried upon a' belt I6I. Mounted over the mat I60 is a spray nozzle I62 adapted to soak the mat with a dilute binder in the same manner as illustrated in Fig. 1. Underlying the belt I6I is an outlet trough I63 adapted to receive the excess binder solution which may drip through the belt I 6I from the mat I60. Mounted near the discharge end of the binder I6I is a frame I65 upon which is mounted a horizontally disposed shaft I66 which may be turned by a crank I61 or other suitable means. On the shaft I66 is mounted a split mandrel I68. The frame I65 also holds horizonta-lly disposed shafts I63 and I10 upon which are mounted rolls HI and I12 respectively. A knife blade I15 and a coacting block I16 are preferably arranged near the discharge end of the belt I6I and serve to sever predetermined lengths of the mat I60.

In the operation of this device, the mat I60 is laid over the mandrel I68 and then wound up After a predetermined length of mat I60 has been wound upon the mandrel, the mat is severed by means of the knife I15. The rolls HI and I12 are adapted to rest yieldingly with a predetermined pressure against the pipe cover I11 and assist in an interfelting of the adjacent layers of the mat I60 which composes the pipe cover I11. After a predetermined number of turns of the pipe cover I11, it is removed from the mandrel I66 and then placed in a suitable drying oven such as, for example, that disclosed in Fig. 8, to dry and harden the binder.

The interfelting of the adjacent layers of mat I68 is performed in a manner similar to that of the other embodiments of the present invention.

The contacting rolls HI and I12 press upon the cover I11 with a predetermined pressure and serve to provide a number of successive relative movements between the concentric layers of the mat, all of these movements preferably being in the same direction. In this embodiment, as in the other embodiments, a. node or slight swelling I18 is formed in front of each of the rolls I'll and I12, these nodes I18 assisting in the interfelting action as pointed out hereinabove with the other embodiments.

Referring now more particularly to Figs. 11 and 12, I have shown another embodiment of the present invention, this embodiment being similar in certain respects to that illustrated in Fig. 8. Instead of having one belt encircling the cylindrical pipe cover, this modification contem-' plates providing two coacting belts, each of which covers aportion of the pipe cover.

More particularly in regard to this embodiment, the apparatus is mounted upon a stationary base I19 at one end of which is a feed table or chute I88. This chute I88 serves to feed pipe covers I8I composed of'a glass wool mat rolled spirally upon a mandrel I82. These may be formed and soaked with binder in a manner similar to that illustrated in Fig. 7. The interfelting device comprises two coacting belts I83 and I84. each covering a portion of the pipe cover. The former is driven over four drums or rolls, I85, I86, I 81 and I88, which are shown in the drawings in solid outline in operative position and in dotted outline in inoperative position. These rolls are all mounted upon a pivoted frame I 89 which pivots about a shaft I98 upon which the drum I85 rotates. The frame I89 is provided with a handle I9I which permits it to be moved into operative or inoperative position as desired and a locking means 288 adapted to lock the frame to the base I19 in the desired position,

The belt I84 is placed diametrically opposite to the belt I83 andis driven around the parallel rolls or drums I93, I94, I and I96, all of which are mounted upon a movable frame I91 which may be oscillated about a shaft I98 over which the roll or drum I96 is mounted. The arrangement of the rolls I93 and I94 is such that in operative position, they are directly over and in register with the rolls I81 and I86 respectively.

In order to hold the frame I91 into position, it has been counter-balanced with the frame I89. For this purpose a chain I99 running over the pulleys I99a. which in turn are mounted on extensions I99b of the base I19, has been provided to connect extremities of frames I91 and I89 respectively. Locking means 288a have also been provided to maintain the frame I91 in its position. It will be noted that with this arrangement a movement of frame I89 causes a. corresponding movement of frame I91 into operative or inop-' erative position, as desired.

Driving means such as a motor 282, may be provided for the belts I83 and I84 and driving connection may be made thereto by means of a speed change'gear box I98, and drive belt 285,

the latter interconnecting the shaft I98 with the shaft I98. In this manner the belts I83 and I84 are driven simultaneously and at like speeds by means of the motor 282. Other suitable driving mechanism may also be provided.

A discharge chute 286 may be provided in proximity to the drum or roll I81 when the latter is in inoperative position, this chute serving to receive the pipe covers I88 after they have lgeen interfelted and direct them to a drying oven to that illustrated in Fig. 8. v

In operating this device, the belts I83-and1 84 are initially in inoperative position shown in dotted outline. During this period the belt I83 is preferably permitted to rotate at a low speed in order to assist the introduction of a pipe roll I8I onto the portion of the belt I83 interjacent the rolls or drums I86 and I81. The frames I89 and I91 are then moved into operative position whereby the belts I 83 and I84 together cover the major portion of the periphery or outer surface of the pipe cover II. The frames I89 and I91 are drawn up to render the belts I83 and I84 moderately taut and then the surface speed of each of the belts is increased, whereby the pipe cover I8I is rotated at a relatively high speed. Small portions of the pipe cover remain uncovered where small nodes or swellings 289 are produced.

The degree of spinning and the speed of spinning may be similar to that indicated hereinbefore in connection with the embodiment il lustrated in Fig. 8. After sufiicient rotating, the belt speed is reduced and the belts parted to inoperative position, whereby the interfelted pipe roll I8I is permitted to pass onto the chute 286 where it is directed into the oven or drier 281.

The centrifuging operation of the coacting belts I83 and I84 performs the functions of distributing the binder solution uniformly over the glass wool fibers, particularly at their points of intersection, and throwingout centrifugally the excess binder solution. Enough binder is permitted to remain, however, to produce a strong, flexible mass, this amount having. been found to be about 2 or 3% of the weight of the fibrous glass, according, however, to the type of binder and the degree to which it is desired to stiffen the mat.

The centrifuging operation performs a further function of interfelting the juxtaposed layers of glass wool mat. The nodes 289 which travel around the pipe cover cause the concentric layers of felted mat to advance relative to one another and cause the fibers thereof to interweave and intermat with one another, whereby the strength and mass integrity of .the mat are materially increased.

Referring more particularly now to Fig. 13, I have illustrated a further embodiment of the present invention adapted primarily to produce cylindrical pipe covers. In the drawings reference character 2 I 8 designates two parallel spaced apart rolls on and between which rests a cylindrical pipe cover 2| I. The pipe cover 2 may be formed in a manner similar to that disclosed in the other embodiments and may consist of a mat of glass Wool wound spirally upon a mandrel 2I2 to which has been applied a sufiiciency of relatively dilute binder.

Arranged in longitudinal contact over the pipe cover 2 and serving to maintain it in position under a predetermined pressure is an idler roll 2I3. The roll 2I3 revolves upon a shaft 2I4 which is mounted at the extremities of supporting levers 2I5, one of these levers 2I5 being provided for each end of the shaft 2I4. The supporting levers 2I5 are pivoted to a frame orbase 2I6 and may be held'in position by means of locking means 2I1 or other suitable means.

The rolls 2 I8 are contained in a vacuum chamber 228 adapted to cause a suction to be applied The drying oven may be similar in design ber 220 leading to a suction blower or other suitable means 222 which carries off the gases and creates a partial vacuum within the chamber 220, At the bottom of the chamber 220 is a trough 223 having a discharge outlet 224 capable of discharging the liquids or other materials which may collect at the base of the chamber 220.

Driving means such as a motor 225 may be mounted on the base 216 and connected with the rollers 2||l through drive belt 226 and belt 221, the latter drive belt 221 interconnecting the two rollers 2|U.

The operation of the device illustrated in Fig. 13 is similar in certain respects to the other embodiments. At the start of the operation, the lever 2|5 is raised and a pipe roll cover 2 is placed between and on the rolls 2|0. It will be noted that the pipe cover 2| l is placed between the rolls 2||| in such a manner that the spirally wound mat upon the mandrel is permitted to wind more tightly upon the mandrel as it is being revolved. I

The roll 2 3 is then lowered upon the pipe cover 2 whereby the pipe cover receives a localized pressure along three sections of its periphery. The motor 225 is then started which causes the roll 2 and the interjacent cover 2 to simultaneously revolve.

The rotation of the pipe cover 2| is preferably carried on at high speed whereby the excess binder solution is caused to move outwardly from the pipe cover by centrifugal force. A large portion of the binder is caused to be discharged into the chamber 220 where it passes off through the conduit 224. The vacuum induced in the chamber 220 by means of the blower 222 assistsin the discharge of the excess binder into the chamber 220. This vacuum is preferably made sufliciently high to cause a substantial draft of air to be induced through the pipe cover between the rolls 2H1. In this manner not only is the excess binder caused to be discharged into the chamber 220 but also the draft of air causes the binder solution which remains to be gradually dried. Moreover, as brought out hereinabove. the movement of excess liquid assists the interfelting of the fibers, particularly the shorter ones.

The removal of the excess binder in this manner assures an even distribution of the binder throughout the mass of fibers, since there is no permanently lower point to which the excess binder may seep.

I have also found that the constant rolling actionon the periphery of the pipe cover 2 durint,- the rolling action, serves to produce a smooth, tough outer surface over which a somewhat larger amount of binder has been caused to accumulate and dry. The resulting product, therefore, is caused to have a very light density and yet have an outer surface which is extremely tough, flexible and strong.

A further important feature of this embodiment is the interfelting action resulting between the adjacent layers of the glass wool mat in the pipe cover 2, caused by the rolling action of the rolls 2H] and 2|4. As the pipe cover 2 revolves, a small node 230 is formed in front of each of the rolls 2H] and 2|3 where it makes contact with the cover 2| The node 230 extends along the length of the pipe cover 2| and rotates relative to and around the pipe cover 2| As a result, the outer layers of mat are caused to advance slightly relative to the inner layers as each node 230 passes thereover.

' hereinbefore, in connection with the other embodiments. Likewise, as brought out hereinabove, the presence of the binder throughout the mass of fibers in the cover 2 causes the adjacent fibers to be lubricated with respect to one another and thereby slip past one another during the lnterfelting action. I have found that this permits a more complete interfelting without causing the fibers to be broken up into shorter lengths, or the pipe cover otherwise destroyed. If, however, the predetermined degree of interfelting has taken place, the solvent for the binder may be dried or evaporated, leaving the binder remaining on the surface of the fibers and causing adjacent fibers to adhere to one another at their points of intersection. The degree of interfelting may be regulated by suitable collars, such as collars I31, illustrated in Fig. 9. The use of these collars also produces a more perfectly cylindrical outer contour for the pipe cover.

Referring more particularly now to Fig. 15, I have illustrated a modified embodiment of a drier adapted to remove the excess binder solution and cause the residue to be evaporated and the adjacent fibers bonded together, principally at their points of intersection to form a flexible coherent mass.

After the pipe covers have been centrifuged or interfelted by any of the means illustrated in Figs. 7 to 13, the pipe covers 245 comprising a concentric mass of glass wool fibers around a perforated mandrel 246 are set in a vertical position on a movable plate 241. The collars I31, the same collars as shown in Fig. 9, may be left on the mandrels to assist the support of the fibrous mass and provide a more perfect air seal. The plate 241 is provided with a series of holes 248 through which the ends of the mandrel project. Thrust bearings or seats 249 are provided in register with each of the holes 248 in order to provide adequate support for the pipe covers 245.

As each pipe cover is inserted in its proper position upon the plate 241, a cap 250 is placed over the upper portion of the mandrel in order to provide a seal and prevent gases from entering into the upper end of the mandrel.

The plate 241-having a full quota of pipe covers 245 is then moved into a drying oven 25| in which place it is shown in Fig. 15. The drying oven comprises a chamber 252 having bearing seats 253 along the side walls thereof adapted to seat the plates 241 and form an air seal therewith. In inserting the plate 241 it may be slid over the bearing seats 253 into position.

The chamber 252 is thereby divided into two portions, the lower portion being a suction chamher 254 in which a vacuum of about 12 to 14 inches of water is preferably maintained.

In order to maintain the desired suction in the suction cha her 254, a blower 255 is provided to withdraw the gases through interconnecting conduits 255.

The lower portion of the suction chamber 254 may be shaped with downwardly converging side walls to provide a trough 251 leading into a discharge conduit 258 through which the accumulated liquids may be discharged and recovered.

The upper portion of the chamber 252 is provided with air inlet means 259 and an air filter 280 adapted to purify the incoming air and eliminate dust particles or other foreign matter. 1

Mounted inwardly from the air filter 260 is a heater 261 through which'the incoming gases or air fiow and. are heated to a suitably high temperature as, for example about 220 F., more or less, of course, as desired. The heater 26! may be heated by any desirable means such as electricity or steam, or the like. For this purpose a steam pipe 262 has been shown adapted to provide suitable amounts of steam.

In operating this device, it is preferable to permit the pipe covers 245 to drain for a short period of time with or without suction, say, aboutfive minutes, in order to permit the first portion of the excess binder to seep down to the lower portion of the 'pipe cover and drain off to a certain extent. At the end of this initial draining period, there may be a concentration of liquid at the lower end of the pipe cover which may be in the neighborhood of 1000% of the weight of the wool and the liquid remaining at the top may be only about 125% of said weight. These figures, of course, are not critical and are only exemplary of the process, more or less residual binder being possible according to the amounts and type of binder and the degree of interfelting and density of the glass wool used.

As the suction is then permitted to act upon the pipe cover, a large portion of the residual liquid drains off through the trough 251 where it may be recovered.

The suction emanating from the suction box 254 causes a large amount of air to pass directly through the interstices of the glass wool fibers of the pipe covers and cleans out to a high degree any residual binder remaining in the interstices of the fibers. The surface tension of the binder solution, however, causes a concentration of the binder to accumulateat the intersections of the fibers where it causes them to be bonded together.

Drying by means of this type of drier has been found to have several advantages. In the first place, the forced passage of air through the glass wool causes the drying operation to be carried out with great dispatch. For example, the complete drying of the covers may be accomplished in a relatively short period of time say, for example, about twenty to fifty minutes according, of course, to the degree of draft and the temperature of the air.

The forced passage of water and air radially through the pipe cover assists in the interfelting action of the fibers themselves and particularly the shorter fibers. The passage of the fluid through the cover in a direction transverse to the initial parallelism or inherent parallelism of the fibers, causes a large percentage of the fibers, and particularly the shorter fibers, to depart from the direction in which they have been left by the interfelting action and approach a more nearly radial direction. It will be noted that after they have been dried and bonded to the other fibers, they are in position and arrangement whereby they may more readily and efficiently assist in increasing the strength of the pipe cover in radial directions.

The forced draft of fluid through the pipe cover also assists in distributing the binder over the surface of the fibers, particularly at the points of intersection of the fibers, and leaves a minimum amount of binder remaining throughout the pipe cover. For example, relatively small amounts of binder, such as 2 or 3, to 8 or 10% of binder,'according to the type and weight of the binder itself, has been found sumcient to form a strong, flexible and coherent mass, and yet leave the interstices free and open and filled with dead air spaces.

It will be observed that the same type of drier embodying the idea of a forced draft through the mat may be provided for drying a planular mat of glass wool fibers such as the mats pro duced by means of the apparatuses illustrated in Figs. 1 to 6.

After the formation of the pipe cover by means of any of the processes illustrated in Figs. '7 to 15, the mandrel may be removed and the cover 235, as illustrated in Fig. 14, maybe slit longitudinally either completely in half or as shown partially therethrough by means of slit 236. With the partial cut as shown, a portion'of the mat 231 remains holding the two halves to-' gether as by means of a hinge. I have found that my interfelted mass of superimposed layers or interfelted fibers is sufiiciently'fiexible and bendable to permit the two halves to be opened and slipped over a pipe 239. The halves are then folded back over the pipe and the momentarily displaced fibers are caused to immediately resume their initial position.

A covering 240 of any suitable material such as canvas, paper, metal foil, paint, fabric, or the like, may be applied, as one skilled in the art would readily understand.

Modifications may be resorted to within the spirit and scope of the appended claims.

I claim:

1. As a product of manufacture, an interfelted mass of glass fibers of varied lengths, some of said fibers being extremely long and lying substantially parallel to the face of the mass, and

shorter fibers throughout said mass extending in all directions interfelting with said longer fibers, the interfelting of said shorter fibers causing said mass to achieve a high degree of mass integrity and a coherence in all directions.

2. As a product of manufacture, an interfelted coherent mass of glass fibers, comprising a plurality of juxtaposed layers of long attentuated glass fibers all lying substantially parallel to the face of said layers and criss-crossed with one another, and a multiplicity of shorter fibers extending in all directions throughout and between said layers causing said layers to be held to ether.

3. As a product of manufacture, a pipe cover having a substantially circular cross-section,

said pipe cover comprising a mass of long at-, tenuated glass fibers criss-crossed with one an-' other and extending predominantly parallel to the outer cylindrical surface of said pipe cover,

and a multiplicity of shorter fibers extending in all directions reticulated and interfelted with said longer fibers to provide a cover having a high degree of mass integrity and flexibility.

4. As a product of manufacture, a pipe cover having a cylindrical outer surface, said pipe cover composed of a plurality of long attenuated glass fibers extending substantially parallel to the outer cylindrical surface of said pipe cover and criss-crtlssed with one another, a multiplicity of shorter fibers interlaced and intermat'ted with said longer fibers and extending in all directions to provide mass integrity and coherence and fiexibility to said pipe cover, and a bonding agent to hold said fibers in position.

5. A pipe cover as claimed in claim 4 in which the adjacent fibers are bonded together mainly at their points of intersection.

6. A pipe cover as claimed in claim 4 in which the fibers arebonded at their pointsof intersection and the interstices between said fibers are left free and open and filled with dead air.

7. As a product of manufacture, a'pipe cover comprising a plurality of substantially concentric juxtaposed layers of long attenuated glass wool fibers, said fibers extending predominantly parallel to the outer cylindrical surface of said tenuated glass wool fibers, said fibers ext-ending predominantly parallel with the outer surface of said pipe cover and crisscrossed and intermatted with one another, a multiplicity of shorter fibers extending in all directions interfelted and interlaced with said layers to form a coherent mass of all of said layers, and a bonding agent adapted to bond said glass filaments at their points of intersection while leaving the interstices-between said fibers open and free and filled with dead air, said bonding agent being plastic clay and being added in amounts less than about 5% by weight of said gloss wool.

9. As a product of manufacture, a pipe cover having a substantially annular cross-section which comprises a spirally wound mat of glass fibers, said mat being wound upon itself in juxtaposed layers and composed of a plurality of long attenuated glass fibers interlaced with one another and extending predominantly parallel with the face of said mat, said layers of said mat being juxtaposed with one another and the fibers of juxtaposed layers being interfelted and interlaced with one another to provide a mass having a high degree of flexibility and mass integrity between the layers.

10. As a product of manufacture, a pipe cover having a substantially circular cross-section which comprises a spirally wound mat of glass fibers, said mat being wound upon itself in juxtaposed layers and composed of a plurality of long attenuated glass fibers interlaced with one another and extending predominantly parallel with the face of said mat, said layers oi. said mat being juxtaposed with one another and the fibers of juxtaposed layers being interfelted and interlaced with one another to provide a mass having a high degree of flexibility and mass integrity between the layers, and a bonding agent dispersed throughout said mass adapted to bond said glass fibers at their points of intersection although leaving the interstices between said fibers open and free and filled with dead air.

11. As an article of manufacture, an interfelted mass of fine glass fibers in the form of a mat, the major portion of said mass consisting of rel atively long fibers extending parallel or approxi-v mately parallel to the face of the mat, and relatively short fibers interspersed throughout said mass, extending generally in all directions and interfelted with said relatively long fibers, said interfelting of the fibers giving mass integrity to the mat and coherence and tensile strength in all directions throughout the mat.

GAMES SLAYTER. 

